Backpack



FIG. 1 is a perspective view of a backpack showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a perspective view showing the inside of the backpack.

The broken lines depict portions of the backpack that form no part of the claimed design. 

CLAIM We claim the ornamental design for a backpack, as shown and described. 